1. Field of the Invention
This invention relates to a magnetic record disk assembly. More specifically, it concerns a floppy disk located within a rigid case having integral case stiffeners, wiping force appliers, floppy disk stabilizers, a cam-operated shutter for covering a transducer access slot, a shutter assembly with a compression spring, and a write protect device.
2. Description of the Prior Art
Floppy disks have been housed in flexible casings, as illustrated in U.S. Pat. No. 3,668,658 that issued June 6, 1972, to Flores, et al. A sponge clamp on a mechanical drive squeezes the casing in the vicinity of a transducer access aperture. This presses a liner within the casing into wiping engagement against a record surface of the disk for cleaning the same. The clamp also stabilizes the disk in a uniform plane just before passing the transducer access aperture so the required transducer penetration will be a constant distance. Rigid housings make such clamps ineffective for providing wiping pressure and stabilizing the disk.
Sony Corporation has attempted to solve the problem of wiper pressure within a rigid casing by using a polyester film (PET, Mylar) leaf spring to press a liner against a flexible disk at one location.
Disk housings have had manually slidable U-shaped clips that form a shutter for sealing the head slot opening. Also, complex shutter-spring mechanisms, have been used as shown in U.S. Pat. No. 3,529,301 that issued Sept. 15, 1970, to Hiruta.
Misreading of information or dropout is a serious problem encountered when transmitting information from a disk into a computer. Dropout is a reduction in output signal level during reproduction of recorded data, sufficient to cause a processing error. Dropout can be prevented and the disk can be maintained in a readily readable condition by (1) keeping dust and other contaminants from settling on the magnetic record surface, (2) cleaning any contaminant that may be present from the magnetic surface, (3) maintaining the record surface of the disk in a uniform plane for a constant head penetration distance, and (4) protecting the magnetic record surface from being subjected to contamination during handling operations.
To maintain a floppy disk in a readily readable condition within a rigid case, sufficient frictional force should be provided between the floppy disk and a wiper for cleaning the disk. The disk should be stabilized in a uniform plane for constant transducer penetration. Shutter means should be provided for sealing the transducer access slot when the magnetic disk assembly is not in use. Simple, automatic means should be provided for opening the shutter means when the case is inserted into a disk drive and for closing the shutter means when the case is removed from the disk drive. A detent should be provided for locking the shutter means in a closed position when the case is removed from the disk drive. A magnetic record disk assembly producing these desired results is the subject matter of this invention.
Known magnetic record disk assemblies include write protect devices that require excessive force to operate and invite the use of fingernails. Such devices are difficult to operate and tend to break the operator's fingernails. Known magnetic disk assemblies have shutter spring assemblies that are difficult to assemble because they include an extension spring that must be anchored at one end to the shutter and at the other end to the case.